Cursor keys: move. Keeping Z or X pressed slows you down which is handy for hard maneuvers
Z: shoot. Shooting consumes energy
X: Whenever you're low on energy, your ship is equipped with a fusion device. Whenever you're near a flying small enemy, you can attempt to absorb it by pressing X. Holding X and releasing when the Charge meter is right on the small green area, allows you to recharge. 2 consecutive MAX Energy recharges, result in a mega bomb.